Artist versus NatureSchenker uses the properties of the harmonic series as outlined in the previous section to explain the natural derivation of the tonal system. Music's basis in nature leads Schenker to develop a metaphor that he returns to throughout his theoretical work.

He portrays the Artist taking the raw materials from Nature and shaping them to make a piece of music. An example of this was mentioned in connection with the harmonic series: Schenker characterised the minor key system as artificial - the artist takes the 'chord of nature' and adapts to his purpose. More significantly, he characterises Nature as offering continuous expansion (the harmonic series which ascends beyond the range of our ears) and the Artist as a controlling force, halting this expansion to create comprehensible musical works. This is what makes Schenker's model of harmony dynamic: instead of static relationships, he proposes this constant process of curtailed expansion.

This is important to his theory for three main reasons:

Firstly, Schenker explains the basic root position triad as, 'a conceptual abbreviation of nature' (Harmony - p. 28) because in the harmonic series it appears spread across three octaves.

Secondly he writes that the rising fifth from the harmonic series suggests an ever-expanding movement sharpwards (i.e. C - G - D etc.) around the circle of fifths. Tonality, he argues would quickly become incomprensible it is for this reason that the artist employs motion in the opposite direction (descending fifths). Ultimately it is this descending fifths that brings music to a close with a perfect cadence (V-I), defying the continuous expansion suggested by Nature

Thirdly, he uses a different metaphor, writing that every note, 'is possessed of the same inherent urge to procreate infinite generations of overtones.' (Harmony - p. 28). What he is suggesting is that, every time a note is played, because it has its own overtone series, it implies a triad. Each note of this triad in turn suggests a new triad. The metaphor is that of life - both animals and plants procreate and Schenker suggests that notes can be understood in the same way. Ultimately, this also means that every note strives to become the tonic in a new key. Again, the artist can allow this natural process to some extent but must ultimately resist the infinite expansion in order that the music he is writing can be intelligible.

Schenker often discusses music in this way, as if notes were organisms with almost human attributes:

'We should get used to the idea that tones have lives of their own, more independent of the artist's pen in their vitality than one would dare believe' Schenker, (Harmony - p. xxv)

This aspect of Schenker's theories tended to get minimised by the American musicians who brought them to the notice of the English-speaking world, but the climate within musical scholarship today (with an increasing interest in semiotics) is more receptive to this sort of speculation. Either way, an awareness of these metaphors is an important part of understanding what Schenker was aiming to achieve.

Finally Schenker's theory of harmony attacks the notion of modulating (or changing key) as confusing and misconceived. This is explained in the next and final section.